Greetings all,
I need a new microphone, and doing my due diligence, I came across a reference, claiming that certain measurement software, namely ARTA, has problems with USB interface, e.g., when doing averaging.
So I am now considering a non-USB microphone. As I understand, they need a phantom power and perhaps an amplifier.
Are there any stringent requirements in regards to the phantom power, e.g., noise, or will one based on 78XX series regulators work? And what about the amplifier?
I am looking at the EMM-6. Any other recommendation?
Kindest regards,
M
I need a new microphone, and doing my due diligence, I came across a reference, claiming that certain measurement software, namely ARTA, has problems with USB interface, e.g., when doing averaging.
So I am now considering a non-USB microphone. As I understand, they need a phantom power and perhaps an amplifier.
Are there any stringent requirements in regards to the phantom power, e.g., noise, or will one based on 78XX series regulators work? And what about the amplifier?
I am looking at the EMM-6. Any other recommendation?
Kindest regards,
M
USB mikes won't let you make dual channel measurements (needed for time reference) and won't help you when you want to make impedance measurements. The easiest way to get around this is to get a USB audio interface. The Behringer U-phoria UMC202HD is -budgetwise- a good option, otherwise I'd pick the Focusrite Scarlett 2i2.
For microphones, the Dayton comes with individual correction curve, which should be just fine.
For microphones, the Dayton comes with individual correction curve, which should be just fine.
As I learned in the Hypex-thread, for all measurements my Focusrite 2i2 is not adequate, whilst the cheaper Behringer U-Phorias are good. I do not remember the thechnical aspects, I think it was timing which is not correct in Scarlett. Look there for further information from a Hypex proto-tester (Class D forum section).
Any EMM-6 or just the calibrated ones? I thought with the Dayton it is the same as with the Behringer ECM-8000: either accept high tolerances or get a three times as expensive hand calibrated with individual curves.
I have experienced the problem you are alluding to (I think). When making a single channel measurement with a USB interface, the impulse drifts slightly in time as recorded by ARTA. The drift in time is slight, but it enough to make the averaging useless. A dual channel measurement may not be subject to this type of drift, but I don't often do them so I am not sure. You can now purchase an excellent quality 2 input channel interface in the MOTU M2 and do dual channel measurements with a mic. The EMM-6 or ECM-8000 would work well with it.
The Scarlett will do fine (it's even in Ivo Mateljan's list...), the key is synchronous AD and DA (one clock). You need the dual channel, because otherwise the software has to decide where your T=0ms is. It does so by analyzing the impulse response and assume that T=0ms at e.g. 20% of the top level of the pulse. That works quite good for tweeters, but with midranges and more so woofers the impulse response isn't a pulse signal exactly and your timing's wrong.
What went wrong with ds23man's measurements I don't know. Could be an exemplary fault or a measurement setup fault. Although he usually knows what he's doing.
What went wrong with ds23man's measurements I don't know. Could be an exemplary fault or a measurement setup fault. Although he usually knows what he's doing.
Not everyone pulls out €800 or more for the appropriate Class 1 B&K, Gras, NTI, Earthworks or even SWBA (experience anyone with that brand?). As for stability, I think that might not be that bad, even for the cheap 1/8" capsules used in many of the budget mikes. Word has been that Earthworks used to select low cost Panasonic capsules only to throw the bad ones away. And B&K uses prepolarized capsules, so why these wouldn't be stable I fail to see.
The EMM-6 correction files can be found here by the way. Note it's no calibration so you'll only get a rough idea of the sensitivity. But at least the curve gets pretty straight.
Hi,
Can you please provide a direct link ( to what you're referencing here ).
I use a 1st generation Focusrite 2i2 and would like to read more about it's technical deficiencies.
Thanks!
Greetings all,
thank you very much for your answers and recommendations.
It seems to me, though, that the alleged advantage of USB interface, i.e., no need for a phantom power - an additional equipment, is negated by needing a USB interface - an additional equipment.
I am thus inclined to go with the EMM-6 or alternative. In that regard, I have been researching the phantom power, and from what I gathered, no stringent requirements are needed, is simply powers the pre-amplifier built into the microphone. Can you please confirm?
Kindest regards,
M
thank you very much for your answers and recommendations.
It seems to me, though, that the alleged advantage of USB interface, i.e., no need for a phantom power - an additional equipment, is negated by needing a USB interface - an additional equipment.
I am thus inclined to go with the EMM-6 or alternative. In that regard, I have been researching the phantom power, and from what I gathered, no stringent requirements are needed, is simply powers the pre-amplifier built into the microphone. Can you please confirm?
Kindest regards,
M
I never said to invest in a Class-I microphone. There are decent microphones for less money that will be stable over a long time. But I can tell you that you should not expect the $50 microphones (like the Behringer ECM8000 and it's younger brothers) to be stable for more than a few months. I learned this the hard way.
Sure. It is indicated in DannerD3H's ' Setting up a Fusion Amp 3-way Step-by-Step', ds23man's first mention of problems with 2i2 2nd Gen begins with poting #17 (linked). From there, just follow the thread. And please let me know if you find to agree with what markbakk said here that it was purely a user error on ds23man's behalf, as I then could confidently use my 1st gen Scarlett, too.
@sheeple,
Thanks!
Seems to me all one has to do to test whether or not a clock is drifting is to make multiple measurements ( over a few days even ) at random times of day >> all the while using the second channel as the T=0 source.
Measurements are made on the same tweeter ( say ) with the mic never moving.
REW spits out a distance measurement ( actually there are 2 ) with the one that removes excess phase being the most accurate of the two ( I believe ) .
There won't be any variation in distance measured ( to tweeter ) if there is no clock drift .
Thanks!
Seems to me all one has to do to test whether or not a clock is drifting is to make multiple measurements ( over a few days even ) at random times of day >> all the while using the second channel as the T=0 source.
Measurements are made on the same tweeter ( say ) with the mic never moving.
REW spits out a distance measurement ( actually there are 2 ) with the one that removes excess phase being the most accurate of the two ( I believe ) .
There won't be any variation in distance measured ( to tweeter ) if there is no clock drift .
Do you have any experience or information/opinion about this mic:
Line Audio Design - Made in Sweden
Gerhard (ds23man) is the only one with big time base drifts. I think the dual channel measurement solves this with this interface. Highly unlikely the left and right channel would drift separately and you have to measure dual channel anyway for a reliable time base. I’m not sure whether he used dual channel, we could ask himSure. It is indicated in DannerD3H's ' Setting up a Fusion Amp 3-way Step-by-Step', ds23man's first mention of problems with 2i2 2nd Gen begins with poting #17 (linked). From there, just follow the thread. And please let me know if you find to agree with what markbakk said here that it was purely a user error on ds23man's behalf, as I then could confidently use my 1st gen Scarlett, too.
I’m not at home with REW either... but one must not forget the impulses are constructed incorrectly when doing single channel.Actually it is a related issue. ..as in Dual-channel measurements relating to analog mic.s vs USB mic.s (which can't do dual-channel because there is only one input: the mic.).
If possible purchase a calibrated (analog) mic. OR just a good (analog) mic. and send it off to get calibrated.
This place is good for calibration, and it's best to get it with the "Pro" version specifically for Sensitivity (for a good reference with respect to loudness):
Cross·Spectrum Labs - Sound | Vibration | Engineering
There are a variety of mic.s at different price-points with the Dayton iMM6 being the very cheapest, and the Dayton EMM6 as the typical go-to mic. on the low-end of mic.s. Neither are particularly good for near-field measurements for low freq.s when considering non-linear distortion testing (..the mic.s overload to quickly).
The one Draki has linked to will be my next mic.. (..and I'll send it off to Cross-Spectrum for the "pro" calibration).
-as you move up in price from there you really have to spend a LOT more to get better.
If possible purchase a calibrated (analog) mic. OR just a good (analog) mic. and send it off to get calibrated.
This place is good for calibration, and it's best to get it with the "Pro" version specifically for Sensitivity (for a good reference with respect to loudness):
Cross·Spectrum Labs - Sound | Vibration | Engineering
There are a variety of mic.s at different price-points with the Dayton iMM6 being the very cheapest, and the Dayton EMM6 as the typical go-to mic. on the low-end of mic.s. Neither are particularly good for near-field measurements for low freq.s when considering non-linear distortion testing (..the mic.s overload to quickly).
The one Draki has linked to will be my next mic.. (..and I'll send it off to Cross-Spectrum for the "pro" calibration).
-as you move up in price from there you really have to spend a LOT more to get better.
I think an analogue microphone is a good idea as it allows for loopback / dual channel measurements and also the sampling frequency is only limited by the interface and not to 48K like most USB mics.
This is the one I use, it is cheap well made and comes with an individual calibration curve, if it is available easily to you I recommend it.
Sonarworks XREF 20 Mic – Thomann UK
I would get a reasonable audio interface too, the Behringer mentioned is good, I have a Focusrite Scarlett and it is good as well. It is worth the small investment. They come with phantom and mic preamps and are useful for so many measuring tasks.
Behringer make a phantom power box for not very much if you already have an interface and mic preamp. If you don't just buy a good cheap interface.
Impedance measurements are really useful and with a good interface they will be quite easy. A headphone amp is a very good way to drive a speaker for impedance measurements as it has the current capability to allow lower noise resistors to be used which makes the results that much better. The headphone output on most interfaces would work for this purpose.
I use an iSEMcon EMM-7101-CHTB with a first generation Focusrite Scarlett 8i6. The microphone works well on the built-in phantom power supply (when using an XLR to BNC adapter which iSEMcon also supplies), but when using the built-in mic preamps, absolute calibration is not going to happen. This is a problem with all audio interfaces that have mic inputs with a gain pot at the front (i.e. all of them), because the exact setting of such a pot changes all the time even if you think you haven't touched it.
However, the Scarlett interfaces that have more than two inputs also have line inputs (at the rear) of which the sensitivity is set using the Focusrite mixer software. You can set their sensitivity to 0 dB, and have the exact same input sensitivity every time you measure. In that case you can, together with the calibration info of your mic and a preamp with exactly known gain, do absolute level measurements. You only have to measure input sensitivity once.
I ended up making a little box that contains a mic preamp, an LM1875 based power amp and two voltage probes and differential line drivers. The mic preamp and the voltage probes have calibrated gain. For convenience, I also included a switch that toggles between impedance measurement mode and response measurement mode, and a selection of 3 current sensing resistors. So measuring a speaker is now a matter of hooking it up, firing up LIMP to measure impedance, flipping a switch and do a dual channel measurement with ARTA. I check calibration every now and then, and find it to be very consistent.
So to make a long story short, if you want to have calibrated inputs, go with a model that has line inputs on the back with software gain settings such as the Scarlett 4i4. These tend to have well reproducible sensitivity, as opposed to the mic inputs that have a physical gain control pot. If you are fine with relative measurements, the 2i2 will serve you well.
However, the Scarlett interfaces that have more than two inputs also have line inputs (at the rear) of which the sensitivity is set using the Focusrite mixer software. You can set their sensitivity to 0 dB, and have the exact same input sensitivity every time you measure. In that case you can, together with the calibration info of your mic and a preamp with exactly known gain, do absolute level measurements. You only have to measure input sensitivity once.
I ended up making a little box that contains a mic preamp, an LM1875 based power amp and two voltage probes and differential line drivers. The mic preamp and the voltage probes have calibrated gain. For convenience, I also included a switch that toggles between impedance measurement mode and response measurement mode, and a selection of 3 current sensing resistors. So measuring a speaker is now a matter of hooking it up, firing up LIMP to measure impedance, flipping a switch and do a dual channel measurement with ARTA. I check calibration every now and then, and find it to be very consistent.
So to make a long story short, if you want to have calibrated inputs, go with a model that has line inputs on the back with software gain settings such as the Scarlett 4i4. These tend to have well reproducible sensitivity, as opposed to the mic inputs that have a physical gain control pot. If you are fine with relative measurements, the 2i2 will serve you well.
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maybe this my problem...My umik is old and my 3 year old plays with it...mic recommendation?
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